WASHINGTON, Dec. 16 (UPI) -- Edith Windsor is an unlikely civil rights hero, but at 83 she finds herself on the front lines of the fight over same-sex marriage.

The U.S. Supreme Court was confronted in the past few months with an array of challenges to the federal Defense of Marriage Act, but at the Obama administration's urging the justices accepted only Windsor's DOMA case for argument.

President Obama, who for a long time opposed same-sex marriage, changed his mind last year, and the administration told Congress it would enforce DOMA as a federal law but would not defend it in court.

A group of U.S. House Republican leaders, called the Bipartisan Legal Advisory Group, has taken up the fight and is defending the act. But the prospect is cloudy.

The Supreme Court by no means is committed to making a constitutional ruling in the case.

In agreeing Dec. 7 to hear argument on DOMA's section 3, the justices said in addition to arguing on whether the act violates the Constitution's equal protection clause, "the parties are directed to brief and argue the following questions: Whether the executive branch's agreement with the court below that DOMA is unconstitutional deprives this [Supreme] Court of jurisdiction to decide this case; and whether the Bipartisan Legal Advisory Group of the United States House of Representatives has [constitutional] Article III standing in this case."

A party only has "standing" if it can show an injury.

The law was enacted in 1996. Section 2, which is not under challenge, says no state is required "to give effect to any public act, record, or judicial proceeding of another state that treats a relationship between two persons of the same sex as a marriage under its laws."

Section 3, which is targeted in all the cases filed at the Supreme Court, says, "In determining the meaning of any act of Congress, or of any ruling, regulation, or interpretation of the various administrative bureaus and agencies of the United States, the word 'marriage' means only a legal union between one man and one woman as husband and wife, and the word 'spouse' refers only to a person of the opposite sex who is a husband or a wife."

After a federal judge and an appeals court ruled for Windsor in New York, the administration asked the Supreme Court to hear argument.

"Although Section 3 of DOMA does not purport to invalidate same-sex marriages in those states that permit them," the administration told the Supreme Court in a petition brief, "it excludes such marriages from recognition for purposes of more than 1,000 federal statutes and programs whose administration turns in part on individuals' marital status. ... Section 3 of DOMA thus denies to legally married same-sex couples many substantial benefits otherwise available to legally married opposite-sex couples under federal employment, immigration, public health and welfare, tax, and other laws."

The Bipartisan Legal Advisory Group of the United States House of Representatives, or BLAG, filed its own petition to the U.S. Supreme Court in a parallel Massachusetts case.

"DOMA does not bar or invalidate any marriages but leaves states free to decide whether they will recognize same-sex marriage," the petition said. "[DOMA does not 'prevent same-sex marriages where permitted under state law.']. Section 3 of DOMA simply asserts the federal government's right as a separate sovereign to provide its own definition, which 'governs only federal programs and funding.'"

BLAG points out that in 1996, "Congress received and considered advice on its constitutionality and determined that DOMA is constitutional" after consulting a number of political and academic sources. "Congress specifically sought constitutional advice from the executive branch, and the Justice Department under the Clinton administration advised Congress three times that DOMA was constitutional."

"Edie" Windsor's case is a demonstration of the practical effects of the act.

In 2007 in Canada, Windsor married her same-sex partner of 40 years, Thea Spyer. When Spyer died in 2009 of multiple sclerosis, she left her estate to Windsor.

As executor of Spyer's estate, Windsor paid approximately $363,000 in federal estate taxes, but filed a refund claim under a federal statute that says "property that passes from a decedent to a surviving spouse may generally pass free of federal estate taxes." The Internal Revenue Service denied the claim because Windsor is not a "spouse" under DOMA's Section 3 and thus not a "surviving spouse" within the meaning of the federal estate tax statute.

In comments since the Supreme Court agreed to hear her case, Windsor has appeared humble but determined -- especially in the face of many who not only consider same-sex marriage illegal, but consider gay and lesbian sex immoral and evil.

Sitting in the Manhattan offices of her lawyers when she heard the news, Windsor said: "I'm this person who believes in the Constitution. I believe in the Supreme Court, and I do expect justice."

USA Today called her "a diminutive blonde with a Betty White smile," and interviewed her in her Greenwich Village apartment. "It's not 'same-sex marriage.' It's marriage," she said. "It's marriage equality. ... From my fourth-grade civics class, I somehow trust the Supreme Court to bring justice."

Windsor worked for years at IBM as a senior computer systems programmer before she quit to take care of Spyer, who held a doctorate in clinical psychology.

In remarks posted on the left-leaning Thinkprogress.org website, Windsor said: "I don't feel it as the start of a legal process. I feel it though, as this great joyous thing going on with the whole gay community. ... The suit is about marriage, my marriage to her, and her marriage to me. It's like magic. It's a magic word, and the whole world understands what it means, so I think it's very important that our marriages exist and can be recognized."

The public is divided on the issue. Last week, a Politico/George Washington University Battleground Poll was released under the headline, "Plurality of Americans support gay marriage," but the results showed a majority opposing gay marriage.

The survey indicated 40 percent "said that same-sex couples should be able to be legally married. Thirty percent thought same-sex couples should be able to enter into civil unions but not be allowed to get married. And 24 percent said they should not be allowed to have any type of legal union," Politico reported.

In other words, 54 percent opposed same-sex marriage.

The poll was conducted by the Tarrance Group and Lake Research Partners, which surveyed 1,000 registered likely voters Dec. 2-6. The poll has a margin of error of 3.1 percentage points, Politico said.

The U.S. Supreme Court is evenly divided by the four-member liberal bloc and four-member conservative bloc. The fate of Windsor's case might come down to swing vote Justice Anthony Kennedy.

Two older opinions written by Kennedy could give an indication of how he would vote.

In 1996's Romer vs. Evans, a number of Colorado municipalities had passed "ordinances banning discrimination based on sexual orientation in housing, employment, education, public accommodations, health and welfare services, and other transactions and activities."

But in a statewide referendum, Colorado voters adopted Amendment 2 to the state Constitution, which banned legislative, executive or judicial action at any level of state or local government designed to protect the status of persons based on their "homosexual, lesbian or bisexual orientation, conduct, practices or relationships."

The affected communities filed suit and a state judge issued a preliminary injunction declaring Amendment 2 invalid. The judge was sustained by the Colorado Supreme Court.

The U.S. Supreme Court, in a 6-3 majority opinion written by Kennedy, said Amendment 2 violated the U.S. Constitution's equal protection clause -- the same ground cited by Windsor in her DOMA challenge.

"We must conclude that Amendment 2 classifies homosexuals not to further a proper legislative end but to make them unequal to everyone else," Kennedy wrote. "This Colorado cannot do. A state cannot so deem a class of persons a stranger to its laws."

In 2003's Lawrence vs. Texas, the U.S. Supreme Court reversed a state appellate court and declared the Lone Star State's sodomy law unconstitutional. In a 6-3 opinion, Kennedy said the statute violated the U.S. Constitution's due process -- or fair proceedings -- clause, and the justice basically told all levels of government to get out of the bedroom.

"Liberty protects the person from unwarranted government intrusions into a dwelling or other private places," he wrote. "In our tradition the state is not omnipresent in the home. And there are other spheres of our lives and existence, outside the home, where the state should not be a dominant presence. Freedom extends beyond spatial bounds. Liberty presumes an autonomy of self that includes freedom of thought, belief, expression and certain intimate conduct."

Still, Kennedy has never written on same-sex marriage, and an article in Slate magazine says analysts on the left and right are worried about how he would come down in the DOMA case, and in the related Proposition 8 case.

Also at the high court's Dec. 7 conference, the justices agreed to hear a case dealing with California's Proposition 8.

California voters approved Proposition 8, the California Marriage Protection Act, in 2008 with slightly more than 52 percent for, nearly 48 percent against. Prop 8 said in part, "Only marriage between a man and a woman is valid or recognized in California."

An earlier, similar measure, Proposition 22, was overturned by a ruling from the California Supreme Court. For Prop 8, opponents went to federal court where a federal judge declared it unconstitutional. A three-judge appeals court panel agreed 2-1.

The petition to the Supreme Court filed by ProtectMarriage -- its sponsor is a state non-profit, California Renewal -- argues the appeals court misinterpreted Supreme Court precedent. It also argues the state has a compelling interest in limiting marriage to a woman and a man.

But, like the DOMA case, the Supreme Court also indicated it is not committed to handing down some sweeping ruling.

In its order accepting the case, the justices said, "In addition to the question presented by the petition, the parties are directed to brief and argue the following question: Whether petitioners have standing under Article III, section 2 of the Constitution in this case."

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